National Geochronological Database sample #857

Core or cutting, Monzonite

Geographic location
-114.995833, 39.256944
114° 59' 45" W, 39° 15' 25" N
White Pine county, NV
Ruth 1:24,000 scale map quadrangle
Accurate to within 1 minute (~1 mile)
NW1/4 NE1/4 SEC. 16, T16N, R62E, DRILL CORE FROM LIBERTY OPEN-PIT COPPER MINE NEAR RUTH , ROBINSON MINING DISTRICT
Source of sample Core or cutting
Rock name Monzonite
Description LIBERTY PIT STOCK. PORPHYRITIC MONZONITE COMPOSED OF ORTHOCLASE, PLAGIOCLASE, QUARTZ AND HORNBLENDE (MANY SMALL INCLUSIONS) PHENOCRYSTS IN A GROUNDMASS OF ORTHOCLASE, QUARTZ, AND BIOTITE (SUBORDINATE TO HORNBLENDE AND OCCASIONALLY CHLORITIC.
Laboratories Lamont (Columbia University)
Compiler name Marvin, R.F.
Date compiled 1975 10
Precision of location Accurate to within 1 minute (~1 mile)
Location comment NW1/4 NE1/4 SEC. 16, T16N, R62E, DRILL CORE FROM LIBERTY OPEN-PIT COPPER MINE NEAR RUTH , ROBINSON MINING DISTRICT
Bibliographic reference Mcdowell, F.W., 1971, K-Ar Ages Of Igneous Rocks From The Western United States: Isochron/West, No. 2, p. 1-16.
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Geologic map unit -114.995833, 39.256944
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K-Ar age determinations

Age estimate 116.84 ± 3Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed biotite
BIOTITE SEPARATE WITH 5% HORNBLENDE
Analytical details
Lab sample ID L-962
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 6.445 %
Radiogenic 40Ar concentration 11.2
Radiogenic Ar 91 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)
Age estimate 109.4 ± 3Ma
age of intrusion
Type of analysis conventional K-Ar
Rock or mineral analyzed hornblende
100% HORNBLENDE SEPARATE
Analytical details
Lab sample ID L-962
Decay constants 4.72E-04, 0.585E-04, 1.19E-04*
K2O concentration 1.01 %
Radiogenic 40Ar concentration 1.64
Radiogenic Ar 90 %
Comments THIS ANALYSIS ALSO REPORTED IN MCDOWELL AND KULP (1967)